A silicon oxide gap-filling process is described, wherein a CVD process having an etching effect is performed to fill up a trench with silicon oxide. The reaction gases used in the CVD process include deposition gases and He/H2 mixed gas as a sputtering-etching gas, wherein the percentage of the He/H2 mixed gas in the total reaction gases is raised with the increase of the aspect ratio of the trench.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A silicon oxide gap-filling process, comprising: providing a substrate having a trench thereon, wherein an aspect ratio of the trench is 4.0 at least; and performing a CVD process having an etching effect to fill up the trench with silicon oxide, wherein reaction gases used in the CVD process comprise deposition gases and He/H 2 mixed gas as a sputtering-etching gas, wherein an ED ratio of the CVD process is 0.03–0.1 and a percentage of the He/H 2 mixed gas in the total reaction gases is 70% at least.
2. The silicon oxide gap-filling process of claim 1 , wherein the CVD process comprises an HDP-CVD process.
3. The silicon oxide gap-filling process of claim 1 , wherein a ratio of He to H 2 (He/H 2 ratio) in the He/H 2 mixed gas is 0.3–4.0.
4. The silicon oxide gap-filling process of claim 1 , wherein the deposition gases comprise SiH 4 and O 2 .
5. The silicon oxide gap-filling process of claim 4 , wherein in the CVD process, a flow rate of SiH 4 is 20–100 sccm, a flow rate of O 2 is 40–200 sccm, a flow rate of H 2 is 100–2000 sccm, a flow rate of He is 200–2000 sccm, a pressure is 5–20 mTorr, a temperature is 400–650° C., a low-frequency RF power is 3000–15000 W, and a high-frequency RF power is 500–5000 W.
6. The silicon oxide gap-filling process of claim 1 , which is applied to an STI process in a 90 nm semiconductor process.
7. A silicon oxide gap-filling process, comprising: providing a substrate having a trench thereon, wherein an aspect ratio of the trench is at least 4.0; performing an HDP-CVD process to fill up the trench with silicon oxide, wherein reaction gases used in the HDP-CVD process comprise SiH 4 , O 2 , He and H 2 , wherein a flow rate of SiH 4 is 20–100 sccm, a flow rate of O 2 is 40–200 sccm, a flow rate of H 2 is 100–2000 sccm, a flow rate of He is 200–2000 sccm, a pressure is 5–20 mTorr, a temperature is 400–650° C., a low-frequency RE power is 3000–15000 W, and a high-frequency RF power is 500–5000 W; an ED ratio of the HDP-CVD process is 0.1–0.03; and a percentage of the He/H 2 mixed gas in the total reaction gases is at least 70%.
8. The silicon oxide gap-filling process of claim 7 , which is applied to an STI process in a 90 nm semiconductor process.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
October 2, 2003
January 24, 2006
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